Elevator Sensor Multi-Stage Detection Trigger
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Solution Overview
Problem
Elevator safety systems face challenges in accurately detecting human presence to prevent false positives and negatives, particularly in scenarios where control of the car or counterweight is lost, requiring a sensitive yet reliable human sensing mechanism.
Innovation Solution
A multi-stage detection trigger system that operates in normal and inspection modes, utilizing a sensor assembly to monitor areas exterior to the elevator car, switching from a first sensing mode with lower sensitivity to a second mode with higher sensitivity upon detection, employing sensors like LIDAR, RADAR, or cameras to capture images at varying frame and spatial resolutions, and focusing on predetermined image features to confirm human presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor assembly operates in high sensitivity mode continuously, then human detection capability is improved, but false positives increase
Solution Approach 1:
The sensor assembly dynamically switches between first sensing mode (lower sensitivity) and second sensing mode (higher sensitivity) based on operational context. During normal operation, it uses the first sensing mode to avoid false positives. When inspection mode is detected or potential hazards are identified, it transitions to the second sensing mode to enhance human detection capability, thus resolving the contradiction between detection precision and reliability.
Solution Approach 2:
The system changes the sensitivity parameter of the sensor assembly based on operational mode. In normal mode, a lower sensitivity threshold is applied to reduce false alarms. In inspection mode, the sensitivity threshold is increased to detect human presence more reliably. This parameter adjustment resolves the contradiction by adapting detection strictness to operational context.
2Reliability
If the sensor assembly uses lower sensitivity mode during normal operation, then false positives are reduced, but detection of actual hazards may be missed
Solution Approach 1:
The sensor assembly dynamically adjusts its sensitivity based on the operational mode detected by the car top control box. During normal operation, it operates in the first sensing mode with lower sensitivity to reduce false positives. When inspection mode is activated, it automatically switches to the second sensing mode with higher sensitivity to ensure hazard detection, thus resolving the contradiction between reliability and detection precision.
Solution Approach 2:
The system changes the detection parameter (sensitivity level) based on operational context. In normal mode, less sensitive detection parameters are used to avoid false alarms. In inspection mode, more sensitive parameters are applied to detect actual hazards. This parameter adaptation resolves the contradiction by matching detection strictness to operational risk levels.
3Measurement precision
If multiple sensing modes are implemented, then detection accuracy is improved, but system complexity increases
Solution Approach 1:
The sensing system is segmented into distinct operational modes (normal mode and inspection mode) with different sensitivity levels. The car top control box detects the operational mode and triggers the appropriate sensing mode. This segmentation allows the system to achieve high detection accuracy when needed while maintaining simplicity during normal operation, resolving the contradiction between precision and complexity.
Solution Approach 2:
The sensor assembly serves multiple functions by operating in different sensing modes. The same physical sensor hardware performs both low-sensitivity monitoring during normal operation and high-sensitivity detection during inspection mode. This multi-functionality eliminates the need for separate sensor systems, reducing overall complexity while maintaining detection accuracy when required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces false positives and negatives by adjusting sensitivity levels based on operational modes, ensuring reliable human detection and safe operation of the elevator system.
Implementation Method 1
the sensor is one of a LIDAR, RADAR, or a camera
Implementation Method 2
the sensor is one of a LIDAR, RADAR, or a camera
Implementation Method 3
the sensor captures images at a first frame rate and at a first spatial resolution
Data Source
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AI summary
An elevator system, having: a car that operates normal and inspection modes; a sensor assembly; a safety chain; wherein while in the normal mode, the sensor assembly: monitors in a first sensing mode to detect whether an object is within a first area, and then monitors in a second sensing mode that is more sensitive than the first sensing mode to again detect the object; and upon determining that the object is potentially human, the safety chain is opened; and while in the inspection mode, the sensor assembly: bypasses the first sensing mode and monitors in the second sensing mode to detect whether the object is located in the first area; and upon detecting that the object is located in the first area, the safety chain is opened.